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Satellites, Remote Sensing and GIS | ISC Class 12

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GeographyISC Class 12 · Communication

Satellites, Remote Sensing and GIS in India (ISC Class 12 Geography)

Updated 18 October 2026 · Fact-checked

Communication satellites in geostationary orbit relay telephone, television, radio and data across India; INSAT and GSAT also give weather forecasts and disaster warnings. Remote sensing gathers data about the earth from satellites such as the IRS series for crops, forests, floods and fishing zones. GIS stores and analyses location data as map layers for planning, hospitals, schools and disasters.

Understand Satellites, Remote Sensing and GIS in India

1. Communication satellites. Placed in geostationary orbit (about 36,000 km above the equator), they relay telephone, television, radio and data signals across the country.

  • India's first satellite: Aryabhata (1975). The Satellite Instructional Television Experiment (SITE, 1975-76) used a satellite to bring educational television to villages.
  • INSAT (Indian National Satellite System) from the 1980s and the later GSAT series: one of the largest domestic satellite systems in the Asia-Pacific region, serving telecommunication, television broadcasting, weather forecasting and disaster warning, and search and rescue.
  • NavIC: India's own regional navigation satellite system.

2. Remote sensing. Collecting information about the earth's surface from a distance, using sensors on satellites or aircraft that record reflected or emitted radiation. Indian Remote Sensing (IRS) satellites (first in 1988), and later Cartosat, Resourcesat, Oceansat and RISAT.

*Uses*: mapping land use and forests; estimating crop area and yield; monitoring droughts, floods and cyclones; groundwater and mineral exploration; urban planning; coastal and ocean studies (potential fishing zones); border surveillance.

3. Four or five ways satellites have revolutionised communication in India

1. Nationwide telephone, mobile, television and radio networks, including remote, hilly and island areas.
2. Weather forecasting and early warning of cyclones, saving lives.
3. Tele-education and telemedicine for villages.
4. Navigation (GPS, NavIC), GIS mapping, e-commerce and digital payments that rely on connectivity.
5. Quick, reliable links during emergencies when ground lines fail.

4. GIS (Geographic Information System). A computer-based system to capture, store, analyse and display data linked to locations on the earth, as maps in layers (roads, soils, population, rainfall). Uses: urban and regional planning, locating schools and hospitals, disaster management, land records, utilities, agriculture, election and census mapping, navigation apps.

5. Remote sensing and GIS together. Satellite images give up-to-date data; GIS layers them with other maps to answer questions such as which villages lie in a flood plain and where a new hospital should go.

6. A coverage sum (imaginary). A geostationary satellite beam covers a region of 2.4 million sq km. If the state to be covered is 3.2 lakh sq km, one beam covers it 24,00,000 / 3,20,000 = 7.5 times over. Roughly 13.3% of the beam (1 / 7.5 x 100) would be enough for the state. (Figures invented for practice.)

Satellites, Remote Sensing and GIS in India: key facts

Satellite uses
  • Telephone, TV, radio
  • Weather and cyclone warning
  • Tele-education and telemedicine
  • Navigation
  • Emergency links
Five ways.
Remote sensing
  • Sensors on satellites
  • Record radiation
  • Crops, forests, floods, droughts, fishing zones
IRS series.
GIS
  • Capture
  • Store
  • Analyse
  • Display as map layers
Location data.

How to answer Satellites, Remote Sensing and GIS in India questions

Use this routine for questions on satellites, remote sensing and GIS.

  1. 1Define the technology in one line.
  2. 2Name Indian satellites or systems: INSAT, GSAT, IRS, NavIC.
  3. 3Give four different uses, with a place or example.
  4. 4For GIS, explain layers and a planning use.

Satellites, Remote Sensing and GIS in India in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Cyclone warning

Suppose a weather satellite shows a cyclone forming over the sea, and fishermen on the coast are warned by radio and phone to stay ashore.

Which role of satellites does this show?

Try it first, then show the solutionSolution
  1. Satellites support weather forecasting and early warning.
  2. Warnings reach people through broadcasting and telephones.

Answer: Weather forecasting and early warning of cyclones, saving lives.

Memory hook: Eyes in the sky protect the coast.

Tricks to remember Satellites, Remote Sensing and GIS in India

Short memory aids. Say each one aloud once, then use it on a question the same day.

  • I-G-I-N

    INSAT, GSAT (communication), IRS (remote sensing), NavIC (navigation).

    Use it when: Matching satellite and use.

  • Layers of a cake

    GIS stacks map layers like layers of a cake.

    Use it when: Explaining GIS.

Satellites, Remote Sensing and GIS in India: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Identify the system · 1 mark · MCQBoard level

India's regional navigation satellite system is:
(a) INSAT (b) IRS (c) NavIC (d) Aryabhata

Try it first, then show the solutionSolution
  1. The chapter lists NavIC as India's own regional navigation system.

Answer: (c)

Example 2: Remote sensing uses · 2 marks · Short answerBoard level

Define remote sensing and state two uses.

Try it first, then show the solutionSolution
  1. Remote sensing is collecting information about the earth's surface from a distance using sensors on satellites or aircraft.
  2. Uses: estimating crop area and yield; monitoring floods, droughts and cyclones.

Answer: Collecting data from a distance; crop estimation and flood monitoring.

Example 3: Beam coverage · 4 marks · Short answerHarder board level

A geostationary satellite beam covers 24,00,000 sq km. A state has an area of 3,20,000 sq km. Calculate how many times the beam covers the state and the percentage of the beam needed for it, and name the orbit height from the chapter.

Try it first, then show the solutionSolution
  1. Times = 24,00,000 / 3,20,000 = 7.5.
  2. Percentage of beam = 3,20,000 / 24,00,000 x 100 = 13.3%.
  3. Geostationary orbit: about 36,000 km above the equator.

Answer: 7.5 times; about 13.3%; about 36,000 km.

Example 4: Four ways · 4 marks · Short answerHarder board level

Explain four ways in which satellites such as INSAT and GSAT have helped a remote island or hill district.

Try it first, then show the solutionSolution
  1. Telephone, television and radio reach the area.
  2. Weather forecasts and cyclone warnings are received.
  3. Tele-education and telemedicine bring services.
  4. Emergency communication continues when ground lines fail.

Answer: Connectivity, weather warnings, tele-services and emergency links.

Example 5: Plan a flood-prone district · 8 marks · Long answerHOTS / competency

Suppose a district is hit by floods every monsoon. Show how remote sensing, GIS and communication satellites can be used together for planning, warning and relief, giving at least five specific uses.

Try it first, then show the solutionSolution
  1. Remote sensing monitors rain, river flow and flood extent from satellites.
  2. GIS layers rivers, roads, villages and elevation to mark flood-prone areas and relief routes.
  3. Planners locate shelters, hospitals and schools using GIS.
  4. Weather satellites give early warnings; INSAT and GSAT carry them by radio, TV and phones.
  5. During floods, satellite links keep communication running when ground lines fail.
  6. Post-flood, remote sensing helps assess crop and land damage.
  7. Navigation (GPS, NavIC) helps rescue teams.
  8. Limitation: poor coverage and low digital skills in remote villages.

Answer: Remote sensing for monitoring, GIS for planning, satellites for warning and links, navigation for rescue.

Where students lose marks in Satellites, Remote Sensing and GIS in India

The slips examiners see most often, and what to write instead.

  • Mistake: Confusing INSAT and IRS

    One is communication, the other remote sensing.

    Wrong working

    IRS satellites give television broadcasts.

    Right working

    INSAT/GSAT serve communication; IRS serve remote sensing.

    Do this: I-G for talking, IRS for observing.

    Usually costs: 1 mark.

  • Mistake: Listing uses without examples

    Examples show understanding.

    Wrong working

    Remote sensing is used for mapping.

    Right working

    Remote sensing is used to estimate crop area, monitor floods and map forests.

    Do this: Name the use.

    Usually costs: 1 mark.

  • Mistake: Repeating one use four times

    Four ways must differ.

    Wrong working

    Telephone; mobile; phones; calls.

    Right working

    Networks; weather warning; tele-services; emergency links.

    Do this: Different heads.

    Usually costs: 2 marks of 4.

Exam tips

  • A common board question asks for four ways satellites have revolutionised communication: prepare five.
  • Match the satellite series to its main use.
  • Define GIS with the word layers.
  • Quote dates (1975, 1988) as given in the chapter.

Practice questions on Satellites, Remote Sensing and GIS in India

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

  1. Q1 · 1 mark · Very short answerBoard level

    Name India's first satellite and the year it was launched, as given in the chapter.

    Hint

    1975.

    Answer

    Aryabhata, 1975.

  2. Q2 · 2 marks · Short answerBoard level

    State two uses of GIS.

    Hint

    Planning and disasters.

    Answer

    Urban and regional planning, locating schools and hospitals, disaster management, land records (any two).

  3. Q3 · 2 marks · Short answerHarder board level

    Why is a communication satellite placed in geostationary orbit?

    Hint

    Position over the equator.

    Answer

    At about 36,000 km above the equator it appears fixed over one place, so it can relay signals continuously across the same region.

  4. Q4 · 4 marks · Short answerHarder board level

    A remote-sensing image shows 4,500 hectares of a 18,000-hectare block under wheat, and the average yield is 3.2 tonnes per hectare. Compute the percentage under wheat and the expected output.

    Hint

    Percentage, then multiply.

    Answer

    Percentage = 4,500 / 18,000 x 100 = 25%. Output = 4,500 x 3.2 = 14,400 tonnes.

  5. Q5 · 4 marks · Short answerHOTS / competency

    A student says remote sensing and GIS are the same. Examine the claim.

    Hint

    Collecting versus analysing.

    Answer

    They are related but different. Remote sensing collects data about the earth from satellites or aircraft. GIS is a computer system that stores, analyses and displays location-based data as map layers, often using remote-sensing images. One gathers; the other analyses and presents.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

  1. 1.Height of geostationary orbit?Show answer

    About 36,000 km above the equator.

  2. 2.Which satellites do remote sensing?Show answer

    The IRS series, Cartosat, Resourcesat, Oceansat and RISAT.

  3. 3.What did SITE do?Show answer

    Used a satellite to bring educational television to villages (1975-76).

  4. 4.What does GIS display?Show answer

    Location-linked data as map layers.

Satellites, Remote Sensing and GIS in India: frequently asked questions

Is NavIC a communication satellite?

It is a navigation system.

What are potential fishing zones?

Ocean areas identified from satellite data where fish are likely to be found.

Do I need dates for all satellites?

Learn Aryabhata 1975, SITE 1975-76 and IRS 1988 as given.